When Bob Dylan wrote, "If my thought-dreams could be seen, they'd put my head in a guillotine," he was expressing a distinction that our culture seems increasingly to blur; namely, that thoughts are not the same as actions, that fantasies are not the same as reality. The Supreme Court's recent ruling that the Child Pornography Prevention Act of 1996 unconstitutionally abridged free speech implicitly reaffirmed these distinctions.

Child pornography was made illegal originally to protect the actual children used in its production. In 1996, however, Congress expanded the definition of child pornography to include computer-generated images -- images not of real children but of virtual ones. The ostensible rationale of the bill was that virtual pornography was used by pedophiles to entrap real children and that the viewing of virtual pornography would stimulate the appetites of would-be pedophiles and increase the likelihood that they would then act out their impulses. The Supreme Court correctly rejected this argument, citing the absence of any credible evidence supporting these claims.

As Justice Anthony M. Kennedy pointed out, if we're no longer simply criminalizing the damage done to real children in the production of sexual images, but also the damage potentially done to them by exciting the impulses of the consumers of these images, then thoughts themselves become the crime. Following that logic, a filmmaker who uses an adult woman to portray a 16-year-old girl in sexual situations (as in the film "American Beauty") is potentially harming children, not on the movie set but in the minds of the film's viewers.

Such a position not only threatens free speech and artistic expression, but it contradicts what we know about human psychology. The problem lies in its failure to differentiate between private experience and public behavior, between fantasy and reality.

Every single day the patients in my psychotherapy practice tell me about thoughts and fantasies that are packed with powerful emotions, from rage and sadness to exuberance and sexual excitement. One patient gets so angry with his father that he imagines taking a shotgun and blowing his father's brains out; another has an exciting sexual fantasy about her next-door neighbor; and still another surfs the Web collecting pornographic images of teenage girls. None of these people has any intention of acting on their impulses.

While fantasies do not predict behavior, they do serve important purposes. The homicidal fantasy of the first patient, for example, expressed his fear and helplessness vis-à-vis his real father. Unable to stand up to him in real life, the patient did so in a dramatic way in his daydreams. The second patient used her sexual fantasy about her neighbor to momentarily escape from a deadening marriage. And the patient who pursued his Lolita fantasies on the Web was desperately trying to ward off feelings of depression. Fantasies are not usually rehearsals for action. Often, in fact, they're substitutes.

Clinical experiences like these are not extraordinary. But they shine an especially bright light on the meaning of sexual fantasies, and they belie the argument that fantasies expressed on the Internet lead to dangerous actions. Such fantasies may be pathological in many ways and may even significantly impair an individual's relationships and life satisfactions, but they are simply not usually a prelude to action.

The pedophilic fantasies portrayed on the Internet offend many people because we know that real children are hurt by the sexual predations of adults, an awareness that has grown in our society as a result of victims speaking out -- witness the current revelations about the Catholic Church.

Fantasies about hurtful actions, however, don't necessarily hurt anyone. Such fantasies may disgust or provoke us, but that isn't sufficient reason to outlaw them. For every instance of bizarre sexual behavior there are a million instances of bizarre sexual thoughts. For every case of actual pedophilia, there are thousands of people, mostly men, with pedophilic fantasies. While it might be true that the sexual abuse of children begins with a fantasy, the reverse is not the case.

Human beings use fantasies to express forbidden feelings and wishes, to master and overcome inhibitions and to creatively find comfort in a private arena that isn't subject to public judgment or sanction. We should put our efforts into apprehending, punishing or treating those people who are hurting children in practice, not in their imaginations.

Michael Bader is a psychologist and author of "Arousal: The Secret Logic of Sexual Fantasies."

We've been hearing a lot lately about so-called "terror sex" or "end-of-the-world" sex, a phenomenon in which some Americans are reportedly now feeling an increased sex drive in the wake of the Sept. 11 terrorist attacks. Following this country's recent catastrophe, the story goes, strangers are reconnecting with a renewed sexual intensity. Reporters, for their part, are alternately speculating that "terror sex" is an attempt to triumph over death, or that we have a biologically programmed human need to propagate the species in the face of threats to our survival, or that fear and arousal are somehow intrinsically linked, or that sex is simply the means by which we re-establish meaning in the face of the unknown.

Of course, the problem with these explanations is that they don't fit with the clinical experience of a psychologist such as myself at all. In the 20 years that I've been practicing psychotherapy and psychoanalysis, I've treated many people who have lived through catastrophes, from survivors of violent crimes, to earthquake survivors, to people who have fled from terrorism in their homelands. On the occasions when these patients do report a parallel increase in sexual intensity, their primary issue isn't biological or existential. Rather, it is about safety. At the deepest level of our psyches, the real reason some of us get turned on by disasters is because disasters make us unconsciously feel safe to be sexual.

In this, those who find themselves especially erotically excited after a tragedy are no different than the rest of us. The human psyche is wired such that sexual desire can only be experienced in a safe context. Safety doesn't only refer to the absence of external dangers, like terrorism, but freedom from internal dangers like guilt, worry, shame, rejection and helplessness. People can't get turned on if they're worried about hurting their partners or feel overly responsible for satisfying them, if they're guilty about being selfish or feel shame, depression or helplessness. As an example, one female patient of mine can only get aroused if she has sex in the dark because the darkness helps her unconsciously feel safe from feelings of shame. A male patient likes to be on the bottom during sex because the image of a strong woman dominating him reassures him against his fears of hurting women. And yet another patient is aroused by taking on the dominant role in the bedroom because it reverses chronic feelings of helplessness. It is only when we feel safe -- albeit momentarily -- from these dangers that we can become sexually aroused.

A patient once told me about an incident in which he and his wife were held up at gunpoint, but managed to escape. This man had struggled on and off his whole life with depression, and his relationship with his wife was secure but rather flat and tepid. That night of the mugging, however, he told me that he was a veritable sexual tiger. When they finally came home, not only was he not depressed, he felt strangely excited. His wife looked different to him, he said. He noticed her body and was aroused by it. "I jumped her," he told me. "She was into it too. We did it on the living room floor. I can't tell you how unusual it was. It was like I almost felt reborn and somehow sex was a part of it."

As we went on to discover, on a certain level, my patient felt that escaping the threat of serious injury or death gave him a reprieve from the self-hatred that lay at the core of his depression. On a symbolic level, surviving a danger felt like he was given permission to be alive, that Fate was saying that he didn't deserve to suffer or die. Momentarily freed of his guilt and self-hatred, he could feel safe enough to get sexually aroused. Often people in his position will believe the adrenaline rush of fear is what is arousing them. But, in all of these cases, what we find is that it is the very surviving of the danger that is so arousing -- not, in fact, the danger itself.

Another patient recounted for me her narrow escape from a building that collapsed during the 1994 earthquake in Los Angeles. The next day, she promptly picked up a man in a bar, took him home and had sex with him, something that she rarely, if ever, did. She told me that normally she would only have sex with a man if she felt that there was some emotional commitment. This time, she wanted to, as she put it, "just get laid." She didn't want affection, she said, just sex. "I felt like men must feel all the time," she told me.

The carnage of the earthquake and the disaster mentality that resulted, we uncovered, made her feel as if the real world's "business as usual" approach to life, and sex, had been suspended. The old rules didn't apply, it seemed; somehow she no longer had to be as hyper-responsible, guilty and careful as she had always been. The psychological and physical dislocations of the earthquake made it safe enough for this woman to temporarily feel safe about being aggressive and hedonistic in the erotic arena. When external prohibitions weaken, we unconsciously feel as if we are being given permission to relax our internal ones. Many of these internal prohibitions, of course, involve our sexual desires.

In our normal day-to-day lives, when it comes to sex, too much familiarity can function like a cold shower in a romantic relationship. Emotional boundaries become fuzzy as people come to know each other inside out, the capacity to maintain a high state of sexual interest is dampened and it is no longer as easy to maintain the sense of surprise and separation that healthy passion requires. Catastrophes change all of this. Nothing is familiar. Everything has changed. People encounter each other as if strangers, and this newfound strangeness is what makes it safer to break taboos, take risks and negate feelings of guilt, shame or rejection. When the "dangers" of familiarity and intimacy temporarily lessen, erotic desire can safely -- and readily -- break through.

At the same time, when disasters loosen our social bonds, threatening not only the familiar, but life itself, the danger of isolation and loss increases. Sexual excitement serves to reconnect people and counteract these dangers, however momentarily. So, when we see lovers reach out to each other for comfort in these post-traumatic times, we witness the extreme, fundamental importance of safety in sexual arousal. While the threat of loss leads to a heightened longing for sexual connection, the loss of familiarity and the disruption of ordinary expectations and rules creates the space that makes such connections more possible. People invariably find ways to weave the many aspects of surviving a tragedy into the safety net necessary for sexual pleasure to flourish.

Recently, my patient Bob came in my office having just arrived home from New York City where he had helped to bury a colleague who had worked on the 75th floor of World Trade Center One. He described the devastation he had witnessed at Ground Zero, the intense sorrow he had experienced at his friend's funeral and admitted to feelings of guilt about the fact that his friend had died and not him. Eventually, he confessed to me, he had also had a bizarre -- and, to his mind, shameful -- reaction when he had offered his condolences to his friend's grief-stricken wife. He had wanted to comfort her, but, at the same time, he had felt the stirrings of sexual excitement. What Bob wondered now was if something in her very helplessness and dependency had turned him on. "If that's the case," Bob opined, "I'm a pervert."

"You aren't a pervert," I explained to him. "Your intense need for comfort and her intense vulnerability in this situation turned you on because it triggered your very real need to be someone's savior. You had a fantasy of rescuing another person through a sexual connection, and the fantasy of saving someone in this way reassures you that you aren't a bad person for having survived, that you can, in fact, heal others, rather than be overwhelmed by their sadness." Bob seemed to visibly relax. "So, then, I'm not a pervert?" Bob asked. "No," I told him, just human."

Dr. Michael Bader is a psychologist in private practice and a contributor to Tikkun magazine. His book, "Arousal: The Secret Logic of Sexual Fantasies," will be published in December by St. Martin's Press.